56减等于42加-搜答案-智慧作业帮

1/2-1/3+1/3-1/4……+1/9-1/10=1/2-1/10=2/5

仔细看就会发现1／6=1／2-1／3,1／12=1／3-1／4...它们是有规律的原式=1+12+1／2-1／3+1／3-1／4+1／4-1／5+1／5-1／6+1／6-1／7+1／7-1／8+1／8

5/6=1/2+1/3,7/12=1/3+1/4,同理可得后面的9/20,11/30,13/42,15/56,17/72.所以原式=1+1/2-(1/2+1/3)+1/3+1/4……-(1/6+1/7

1/6+1/12+1/72+1/30+1/20+1/42+1/56=(12+6+1)/72+(3+2)/60+(4+3)/168=19/72+1/12+1/24=(19+6+3)/72=28/72=7

1/6+1/12+1/20+1/30+1/42+1/56+1/72+1/90=(1/2-1/3)+(1/3-1/4)+(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)+(

不晓得你是不是少了个1/30若果是就再加1/30 如过不是就是这个答案

=1/1×2+1/2×3+1/3×4+1/4×5+1/5×6+1/6×7+1/7×8+1/8×9+1/9×10=1-1/2+1/2-1/3+1/3-1/4+1/4-1/5+1/5-1/6+1/6-1/

1/6+1/12+1/20+1/42+1/56+1/72+1/90=(2+1)/12+(21+10+7.5)/420+(10+8)/720=1/4+11/120+1/40=(30+11+3)/120=

1002-992+982-972+.22-12=50*10=500,可以看成50组,不看每个数字个位的2,前面正好是100到1,每两个一组共50组

因为1/30=1/5-1/6;1/42=1/6-1/7;1/56=1/7-1/8;1/72=1/8-1/9所以,原式=1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9=1/5-1/9=4

1-1/6+1/42+1/56+1/72=5/6+1/42+1/56+1/72=6/7+1/56+1/72=7/8+1/72=8/9

32加56等于

八十八再答：��л

1/2+1/6+1/12+1/20+1/30+1/42+1/56=1/(1*2)+1/(2*3)+1/(3*4)+1/(4*5)+1/(5*6)+1/*(6*7)+1/(7*8)=1-1/2+1/2-

56加568等于

624

[4]×[8]-[4]=96÷[4]+[4]=[28]5+8+9=1×（2+3+4+6+7）

3/4+1/4-1/5+1/5-1/6+1/6-1/7+1/7-1/8+1/8-1/9=3/4+1/4-1/9=8/9

原式=1/（6*7）+1/(7*8)+1/(8*9)+1/(9*10)+1/(10*11)+1/(11*12）=（1/6-1/7）+（1/7-1/8）+（1/8-1/9）+（1/9-1/10）+（1/

1/20+1/30+1/42+1/56=(1/4-1/5)+(1/5-1/6)+(1/6-1/7)+(1/7-1/8)=1/4-1/8=1/8

八分之一再答：真的

这个不难掌握方法就行

56减 等于42加